Summary of Work: Some studies now suggest that early sepsis, which is characterized by an excessive inflammatory response, may be followed by a period in which immuno-responsiveness and host defense are depressed. This depression is speculated to predispose the host to additional infection. Whether such a state exists and whether, if present, it is reversible with the administration of immunostimulatory agents is now debated. Using a multifactorial study design in a rat model, we plan to study the effects of an initial episode of bacterial infection and sepsis on the host's susceptibility to later infection. As part of this same study, we also plan to study the effects of granulocyte colony stimulating factor or granulocyte-macrophage colony stimulating factor administration on later susceptibility to infection. Due to problems developing an MTA with Amgen this past year, this study was not conducted. However, arrangements for one are now underway; when complete, this study will move ahead.